15990949561 has 2 divisors, whose sum is σ = 15990949562. Its totient is φ = 15990949560.

The previous prime is 15990949523. The next prime is 15990949627. The reversal of 15990949561 is 16594909951.

15990949561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11630328336 + 4360621225 = 107844^2 + 66035^2 .

It is an emirp because it is prime and its reverse (16594909951) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15990949561 - 2⁹ = 15990949049 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 15990949496 and 15990949505.

It is not a weakly prime, because it can be changed into another prime (15990949661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7995474780 + 7995474781.

It is an arithmetic number, because the mean of its divisors is an integer number (7995474781).

Almost surely, 2^15990949561 is an apocalyptic number.

It is an amenable number.

15990949561 is a deficient number, since it is larger than the sum of its proper divisors (1).

15990949561 is an equidigital number, since it uses as much as digits as its factorization.

15990949561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3936600, while the sum is 58.

The spelling of 15990949561 in words is "fifteen billion, nine hundred ninety million, nine hundred forty-nine thousand, five hundred sixty-one".